1. Field of the Invention
The present invention relates to a method and a system for preventing malicious communication.
2. Description of the Related Art
Most users receive a lot of e-mails due to the prevalence of the Internet, which also provides a way for those so-called hackers to embed or to attach “malicious software” (including common viruses, Trojan horses, backdoor programs, leaks) for attacking computers of victims.
Generally, users would use firewalls to protect their network infrastructure and to prevent outside hackers from linking to their computers. However, if users behind a firewall actively initiate a communication to the Internet, the firewall cannot provide proper protection. Usually there's little limitation for a user to initiate an outward communication. Otherwise, the user will find it difficult to use the Internet.
The Internet Protocol (IP) comprises four set of digits, for example 201.105.194.134, which is hard for users to remember. Therefore, domain names consisting of words or characters (http or URL), such as www.example.com, provide users with a more convenient way to remember the site address. A domain name server (DNS) is provided for translating a domain name (or universal resource locator, URL). For example, the DNS refers www.example.com to 201.105.194.134. When a user types the site address (for example: www.example.com), the DNS refers it to the corresponding IP address (for example 201.105.194.134) to complete the Internet connection.
In order to meet different requirements such as using a floating IP address, dynamic DNS (DDNS) is provided for users to link to non-static IP addresses. For example, www.example.com corresponds to 201.105.194.134. When the server using that IP address is under maintenance for a week, it is necessary to redirect linking requests to another server (for example 201.105.194.136). While users can use DUNS to change the IP address corresponding to www.example.com to 201.105.194.136 and to switch back to the original 201.105.194.134 thereafter. Here, users can set the Time To Live (TTL) value to be one week.
Hackers often exploit these linking behaviors to embed or to attach malicious software to initiate automatic connections of the victims' computers to the Internet to attack the victims' computers.
Therefore, it is advantageous to provide a way to solve the security problems.